The Fine Description Of Yanan Group-Yanchang Group Of Hanqu-Zhangtianqu Oil Region In Ordos Basin

Yanan group and Yanchang group of Han-zhang Oil Field in Ordos Basin was taken as the study object in this thesis.Multi-discipline such as reservoir geology,development, sedimentology,logging,reservoir engineering,modern oil well testing and indoor experiments were integrated,performance and static state were united to deeply research sedimentary facies,microtectonics,reservoir,flow unit and oil remaining,and to develop a set of research ideas and technologies on the remaining oil distribution and reservoir description in the structure-lithology reservoir in Ordos Basin,which will offer reference to the similar research..The main understanding and conclusions are as follows:1.Not sufficient datum and disrelation of criterion of stratigraphic classification was offered in Region of interest because of individual development a few years ago.After various difficulties were overcomed,according to unified criterion,layer of Yanan group and Yanchang group were firstly divided into 11 layers such as Y8,Y9¹,Y9²,Y10¹,Y10²,C1,C2^1-1,C2^1-2,C2^1-3,C2²,C2³,and builded formation detailed framework of whole region;2.Microtectonics of each subzone of Yanan group and Yanchang group were firstly researched systematiely and deeply,different types of microtectonics were formed by affect of differential compaction and tectonic stress,variable regular pattern of plane and section were described finely,meanwhile mechanism of gas-oil inrichment and oil remaining distribution was studied;3.The reservoir characteristic of deposition,petrology,paleontology,logging geology, and the geometry of the sand body were analyzed systematically,of which indicate that Yanan group is river facies deposition,which different from previous deltaic plain,and Yanchang group is deltaic plain;meanwhile,The reservoir depositional microfacies,the rock-electrical characteristic of different sedimentary body are researched.Four electrofacies models were summarized;Y9,C1 and C2 were belonged to type ofâ…¢and Y10 to type oâ…¡;4.The reservoir characteristic of petrology,composition of pore throat,diagenic metamorphism,heterogeneity,oil character,electric nature,relative permeability curve, water displacing oil,wettability were firstly studied synthetically,based on these, distribution characteristic and variable regular pattern of plane and section of the heterogeneity of the layer-in,interformation and horizontal,oil saturation and flow unit and their influential factors were described deeply,generally and finely.The criterion of reservoir delineation was made and types of its were divided by three types and types of each member were classified according to this criterion.5.Based on previous study,reservoir flow units were closely analyzed and include the development and dynamic testing data into the classification criteria and the new method of multiparameter clustering eanalysis was adopted,of which made the criteria more reasonable.Four types of flow units in the study area were identified,furthermore,the relationship among depositional microfacies,oil remaining distribution and flow units are discussed;6.Types of structure trap and drive of were analyzed systematicly,of which indicate that The traps of Yanan group and Yanchang group both are mainly structure-lithology trap and lithologic trap,drive type of Yanan group is mainly edge- bottom drive types and which of Yanchang group is elasticity- dissolved-gas drive;7.Based on the research of the types and characteristic of oil remaining distribution, proposed that the main factor of remaining oil forming include reservoir and development no-balance.Distribution of remaining oil is controlled by depositional microfacies,which is mainly in thin sand of edge river and interchannel in plane and in the upper of direct cyclic deposition in section because of higher water flushed degree.Distribution of remaining oil of C2^1-1and C2^1-2is mainly in thick sand of main stream channel because of late development.